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Mark Bisig
Mark Bisig, Auto Service Technician
Category: Chevy
Satisfied Customers: 158
Experience:  28 years at a Chevrolet Dealer, ASE Master Technician, GM Master Technician
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1999 chevy: z71 4x4 trouble code

Customer Question

1999 chev silverado z71 4x4 trouble code po449 what does it mean and what direction to go
Submitted: 9 years ago.
Category: Chevy
Expert:  Mark Bisig replied 9 years ago.

HelloCustomer This code is for the evap vent solenoid. The common part to go bad here is the vent solenoid itself. Here is the procedure to replace it.

Evaporative Emission Vent Valve Replacement

Replacement Procedure

  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Disconnect the evaporative emission (EVAP) canister vent electrical connector, if equipped.
  3. Disengage the 2 vent valve pipe clips securing the pipe to the underbody.

    Remove the clips from the underbody and discard.

  4. Disconnect the vent valve pipe at the EVAP canister.
  5. Remove and retain the EVAP canister vent valve bracket mounting bolt.
  6. Remove the complete EVAP canister vent valve assembly with bracket attached and discard.

    Notice: Refer to Fastener Notice in the Preface section.

    Object Number:(NNN) NNN-NNNN Size: SH

    Important: The new canister vent valve will be installed in a new location, outside of the frame.

  7. Position and secure the new valve assembly to the frame bracket on the outside of the frame using the existing hole and mounting bolt.

    Tighten the bracket mounting bolt to 12 N·m (106 lb in).

  8. Connect the vent valve pipe to the EVAP canister.
  9. Install the 2 vent valve pipe clips into the existing underbody holes.
  10. Connect the EVAP canister vent valve electrical connector, if equipped.
  11. Attach a bulk 5/8 in heater hose to the vent valve port and secure using a clamp.
  12. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
    Object Number:(NNN) NNN-NNNN Size: SH

  13. Secure the filter box to the fuel lines above the transmission using a tie strap.

    The filter box opening should be pointing downward.

  14. Tie strap the hose as needed along the frame rail in order to keep the hose away from the pinch-points and heat sources.
  15. Lower the vehicle.